Heavy fuel usage/high revs

[Keith Mitchell]

Hello, have a 2014 YRS, 1.5 auto, just curious as according to different websites I should be averaging between 6 and 6.5 l/100kms. The car has a ?42 litre tank so if it was achieving this I would assume approx 700km/tank. This car is lucky to get 350..
some things I have noticed, at highway speeds (110km/hr) the engine is raving at approximately 3000rpm. This seems very high. I also have a 2012 Camry and at the same speed it revs at 2200.. is this little Yaris not going into top gear?
When travelling at 80km/h (sometimes even slower speeds) on a downhill and I use the brakes the transmission will drop a gear for no reason.
I’m suspecting transmission issues or a manifold leak of some type? Any help from others experiencing the same issues..